Efficiency of nuclear plants well worth considering

In a guest column Jan. 17, the writer noted that the Connecticut River below the Vermont Yankee nuclear power plant was ice-free, whereas upstream of the plant the river was frozen. Heat discharged from the plant created an ice-free plume downstream, he wrote, and noted that the plant runs at about 33 percent efficiency in producing electricity, meaning that 67 percent of the energy goes into the river as heat.

The writer compared this performance to conventional non-nuclear power sources that he said approach 70 percent efficiency.

This is impossible. Physics requires that whenever water is boiled to produce steam to drive a steam turbine, heat must be rejected to a lower temperature heat sink, whether it is the atmosphere, an ocean or a river.

This holds for all energy sources, be they nuclear, coal, gas or solar. To achieve a much higher efficiency than 33 percent would require a much lower temperature sink. On the other hand, cogeneration power plants, such as that at the University of Massachusetts, utilize the rejected heat for heating buildings while at the same time producing electrical power, giving an overall efficiency of about 85 percent. Cogeneration should be considered in designing all electrical power plants.

The writer goes on to say that the mining of uranium and the construction of nuclear plants requires tremendous use of fossil fuel energy. How much?

Compared to other means of producing electricity, over the life cycle of a nuclear plant, including uranium mining and enrichment, construction, operating and decommissioning, a nuclear plant results in less carbon dioxide than hydro, wind, solar and biomass and less than 1/100 of fossil fuels for the generation of equal amounts of electricity.

For our planet’s sake, advanced modular nuclear plants should be in our future.